Speedometer



R. Q. E Q QLG ELEV SPEEDOMETER Filed June 22, 192,8

Patented May 27, 1930 I UNlTEl ST TES RALPH O. I'IELGEBY, OF FLINT, MICHIGAN,

earn osrics ASSIGNOR TO A G SPARK PLUG COMPANY,

OF FLINT, MICHEGAN, A COMPANY OF MICHIGAN SPEEDOMEIER Application filed June 22,

his invention relates to measuring instruments and has been designed as an improve ment in a magnetic speedon'ieter employing a rotating magnet.

An object of the invention is to simplify the construction of the speed indicating part of such an instrument. Another object is to make use of a minimum number of parts.

ther objects and advantages will be understood from the following description and the accompanying drawing.

ln the drawing:

Figure l is a vertical central sectional view of the speed unit with parts broken away;

Figure 2 is a top plan view of the mechanism shown in Figure 1;

Figure 3 is a fragmentary side elevation of the magnetv showing the thermostatic compensator in place;

Figure 4c is a vertical central sectional view of a modified form;

Figure 5 is a top plan view of the invention shown in Figure 4:;

Figure 6 is a sectional view on line 6-43 of Figure l, parts broken away; and

Figure 7 is a fragmentary sectional view on line 77 of Figure 5.

The drawing illustrates only so much of the measuring instrument as is necessary to lisclosethe invention. The outer casing, the odometer mechanism usually associated with a speedometer, the driving connections and other related parts are not shown.

Referring by reference characters to the :lrawing and first to Figures 1 t0 3, inclusive, numeral 9 designates a lie cast frame used to support the speed indicating mechanism. and the odometer, not shown. In an opening in frame 9 is rotatably mounted a worm 11. At its upper end this worm carries the hub 12 to which is fixed a magnet 10. The magnet is flat and of annular shape *ith an. opening in the annulus to provide 1 oles.

T his worm continues downwardly as a shaft 18 through a,.suitable bore formed in frame 9. The lower end of shaft 13 is adapted to be connected to and driven by a conale cable, the flexible cable and the connection between the cable and shaft 1828. Serial No. 287,629.

13 being omitted since these details do not constitute a part of this invention.

A retaining clip 1 f engages a circumferential groove in the worm shaft and is positioned by the frame 9 to hold the worm from axial movement.

Positioned over the magnet and centered in the axis of shaft 13 is a speed cup 16. This speed cup is open at its top, in this respect differing from the prior constructions by being inverted. The cup is carried by a spindle 17, which is journaled at its lower end by suitable bearings l cated in the upper end of the worm shaft. At its upper end, spindle 17 is journaled by a bearing located in the upper jewel frame 18. The spindle 17 projects through frame 18 and fixed thereto outside the frame 18 is a hub 20, to which is fixed the inner end of a coiled hair spring 21. he other end of hair spring is secured to an up-turne-d arm 22, which is stamped from jewel frame 18.

Stamped from jewel frame 18 is another I arm 23, which is an 'ularly turned in a downward direction into the path of an lip-turned ear stamped from the speed cup 16, to act as astop for limiting the rotation of the speed cup.

will be seen from Figure 2 that the frame 18 is substantially circular in shape and is .oned within the open speed cup. From ircular portion a plurality ofupwardly directed arms 18 extend and the ends of these arms are outwardly bent and secured to the frame 9 by fastening means 9.

t will also be noted. that beyond the periphery of jewel frame 18 the underlying speed cup is depressed to form an annular pocket 16 and a circular recess 16". It is within this circular recess of the speed cup that the magnet is located. It will therefore be seen that within the axial extent of the speed cup are included the magnet, the hair spring, and substantially the whole of jewel frame 18.

Positioned in the polar gap of the magnet is a temperature compensator 25 of known characteristics, this compensator being preferably in the form of an alloy to correct for variations in magnetic permeability and in- 1' nether, shown, and is fixed the counterpart of clip lei.

33 extendi n tended to overcome inznrcuraciei peed cnp readings, which would oth cur with temperature changes.

'n-eferably formed of two pic by being; engaged with the hut 'ihe rotor shaft 13 1E mated by an oil wick 45 secured in position a The construction is very compact, very siunple and comprises but few parts which may he economically manuractured and 02 s- I ily assembled.

1 J1 tne shalt at its upper end, in Figure l. Spindle 2T. wh'ch carries the speed cu, 36. 1S ournaled 1 at its low 1 end in the worm shaft, and at its upper on d to a hole jewel carried by hearii p- 8 located in the jewel frame 28. T he spindle raping clip 29 is secured to the frame 26 by fastening means 29. This clip has two arms, one arm retaining the spindle movement, as shown, ELDL 1-he other arm being bifurcated. The furcations of the otl earm engage a stamping 30 which constitutes a s1 ring regulator. This second arm of stamping 30 holds the regulator stamping for rotation about bearing; 28. The end of arm 30 is attached to the hair spring 31. The other end of the hair spring is secured to a hub carried by the spindle 27.

A circular cap member is positioned witl'lin the speed cup 36 closely adjacent the bottom thereof. his member has two upwardly directed legs terminating; in ears through openings in the frame said being oppositely directed whcreby they rve to clamp the member in fixed pos in relatively the frame 2o. An car 38 stamped and upset from part lie in the pa th of an ear 39 stam ec up from tl e speed cup. The en gapgement of these parts 38 and 39 serves to limit the rotation of the speed cup.

he cup is provided with a circul: r depr "sion on its outer lower side within which is the annular shaped magnet 4:0. in this case, as in other. there is a temperathe ture compensator l l secured with the magnet to the hub 42 carried by the worm shaft, the compensator being located between the poles of the magnet, as shown in Figure 6.

In both forms of the invention, the speed cup is upwardly open and houses the ewel frame and hair sprin In both, the magnet is received within a depression of the speed cup. in the form shown by Figure l. adjustahilit-y of the hair :-;prjing is provided for by the add d part 30. In this second form, aiso, the s adjustable. 30th forms of tne E efficient, sn'nple in construction ,nd ,HSi y assembled.

I claim:

1. In a measuring instrument, l'Ol'ZZlJZllLlG speed indicating cup, an independently rotatable :u'mular mag-net influencing; the r0ta tion of said cup, said speed euphavina' a, closed bottom provided with a depl sion. and the rotatin magnet being positioned concentric with the cup and in said depression.

2. The invention so; forth in claim 1, a rotor s i carrying said uwgnct, an upper jewel frame positioned within 825i speed cup, a spindle mom ting said speed cup, hearings for sa d spindle i n the upper end of said rotor shaft and in said jewel frame.

3. In measuring instrument, a frame, a rotor shaft journaled in said frame, an an nular m et carried by said shaft, a speed cup, a sp... .dle the :for, the speed cup having an outer depression in its bottom wall to house said magnet, a j cwel frame within said cup, said spindle journaled axially of said rotor shaft, at one end in said shaft and at its other end. in said ewcl frame.

41:. In a meas iring' instrument, a rotor shaft, an annular magnet, said magnet carried by said rotor shaft, 2 speed cup open at its upper end, said s eed. cup having a depression in the outer face of its bottom wall, the magnet hemp; located in said depression, said speed cup having; a spindle, fixed jewel frame within the cup, the spindle j ourn aled axially of the rotor shaft, within the shaft and in the jewel frame, a hair spring connected at one end of sait spindle ant within said cup, means associated with said jewel frame to hold the other end of said. hair spring.

5. In a measuring ins rument. a rotatahly mounted speed cup hayi': Y an annular wall and a closed, l'aottom, an independently roata e annular niap'a'iet within an outer depression of said hottom wall, a jewel frame within said cup, and a hair spring to restore said speed cup to a predetermined position. said hair spring); located within said cup.

6. The invention forth in claim 5. said speed cup having an inner annular recess adjacent its annular wall, co-operating parts RALPH o. HELGEBY. 

